A site where a man with far too much interest in beer gets to write about it.

Wednesday, 17 August 2016

The Great British Beer Festival 2016

You might think that as a brewer going to the Great British Beer Festival counts as Continuing Professional Development. And you'd be right. But even more so when you stop part way to go to a lecture.

This year it was on how Ageing Flavours Begin in the Mash Tun*.

Continuing Professional Development

The lectures have been happening for a few years and I think this was the best one yet. Here's my notes:

The cardboard flavours found in ageing beers are caused by carbonyl compounds created during the brewing process. They cannot be tasted early on as they are bound in chemical complexes. They come from the oxidation of fatty acids to aldehydes in the mash tun and downstream and lipoxidases having a similar effect if there's a protein rest. Strecker reactions can also cause aldehydes to be formed from amino acids. Maillard reactions are also involved.

To minimise formation of staling compounds oxygen ingress should be kept to a minimum during brewing. CO2 purge the mash tun, bottom fill the copper and use deaerated liquor for mashing. Having a valentine arm or variable speed pump on the mash tun is better than partially closing a valve as this causes a partial vacuum in the pump and encourages DO pickup. Don't over oxygenate wort, and oxygenate it when the yeast is ready to grow.

Higher mash temperatures slow down lipoxidase activity, so use well modified malt that doesn't need a protein rest. Also this will reduce TSN which is a substrate for Stecker aldehydes.

Aldehydes are more soluble in alkali solutions so acidfy sparge liquor to pH5 (using lactic acid) and get the CaSO4 right for the mash. Aldehydes are loosely bound so a good boil strip them out, get at least 7% evaporation. Keep whirlpooling to a minimum. Good trub formation will also help pull out aldehydes.

Maltsters can also help by suppressing rootlet growth and Null lox malt is also available which is made from barley which has had a staling enzyme bred out of it. Keep copper and iron levels low in the brewhouse as they encourage oxidation, and remember that yeast only mops up oxygen during maturation if it's at at least 12 degrees C.

Fascinating eh? Now back to the beer:

One highlight was managing to track down the revived version of Draught Burton Ale. It wasn't a bad effort, and they've certainly got the hops right but it was a bit dryer and lacked the slight sweetness than Burton at its best had.

More CPD

But more importantly than that, yes even more important than reviving Burton, I had to check out the Old Dairy Snow Top. As it won its category in the Winter Ale festival we thought it was probably in the Champion Beer of Britain competition.

Maybe if I crop this enough people won't notice it's an old picture from a pub

Rather irritatingly CAMRA had moved the results announcement to the evening do so I went home none the wiser. On checking twitter when I arrived I saw my ex-colleague Chris Bingham had won the Supreme Champion prize which delighted me. And then scrolling down a bit further I saw Snow Top was runner up. Despite what that prick Piers Morgan says the silver medal in the Supreme Champion Beer of Britain competition sounds pretty good to me. In fact I'm smiling as I type.

* Based on the paper "On the Origin of Free and Bound Staling Aldehydes in Beer" Baert, JJ et al. Jouranl of Agricultural and Food Chemistry, 2012.

I must confess I'd never given much concern to brewhouse aeration before, so there was certainly a lot of food for thought from the talk. There's much more detail in the paper though so get Julian to send you a copy, or come to think of it drop me a line and I can forward it on.